Merge pull request SharePoint#5910 from JoanneHendrickson/patch-49

update migration-isv-guidance.md

Author: andrewconnell

docs/apis/migration-isv-guidance.md

@@ -1,5 +1,6 @@
 ---
 title: "Migration guide for ISVs"
+ms.date: 06/18/2020
 ms.reviewer: 
 ms.author: jhendr
 author: JoanneHendrickson
@@ -88,11 +89,17 @@ There are two kinds of enumeration queries, assuming the client intends to read
 
 To query for every item in the list, recursively – in other words, the order does not depend on which folder(s) the items are contained in – the query should sort by ID.
 
-    <OrderBy Override="TRUE"><FieldRef name="ID"/></OrderBy>
+`<OrderBy Override="TRUE"><FieldRef name="ID"/></OrderBy>`
 
 To query for every item in a specific folder, the query should sort by the filename, **FileLeafRef**.
 
-    <OrderBy Override="TRUE"><FieldRef name="FileLeafRef"/></OrderBy>
+`<OrderBy Override="TRUE"><FieldRef name="FileLeafRef"/></OrderBy>`
+
+## Permission guidance
+
+You need to be aware of three key numbers as you plan your migration to OneDrive or SharePoint especially when you have a hierarchy of deeply nested folders. They are: (1) the number of SharePoint unique permission scopes, (2) the number of role assignments, and (3) the total number of items in a list or library. Read the full guidance:
+
+- [Migration permission guidance](https://docs.microsoft.com/sharepoint/dev/apis/migration-perm-guidance)
 
 
 ## For migrations over 100TB